Genetic Model and Development Potential of the Guantao Formation Sandstone Geothermal System in the Zhongmu Sag,Kaifeng Depression
Research on the genetic mechanisms of geothermal systems and the detailed evaluation of geothermal resources are fundamental to understanding the efficiency of regional geothermal development.In this study,the Zhongmu Sag in Kaifeng Depression is chosen as a case study.Based on the regional geological structural char-acteristics,and combined with data from geothermal wells and hydrochemical analysis,factors such as the geo-thermal field,thermal reservoir distribution,and hydrochemical characteristics of the sag are analyzed.We also developed a conceptual model of the geothermal system and carefully evaluated the geothermal resources using a stratification approach.The results indicate that the heat source of the geothermal system in the Zhongmu Sag is primarily derived from heat conduction in the crust and mantle,with a heat flow value of approximately 45-65 mW/m2.The Jiaozuo-Xinxiang-Shangqiu fault in the northern Zhongmu Sag served as a favorable channel for the upward transport of deep heat flow.The thermal reservoir is the Guantao Formation sandstone,which is consistently distributed throughout the area.The depth of the reservoir floor ranges from approximately 1600 to 2200 m.Between 30 and 48 vertical sand layers can be identified within the thermal reservoir.They have a cumulative thickness of approximately 130-420 m,a porosity ranging from 16％to 32％,and a reservoir thickness ratio of up to 67％.The thermal reservoir of the Guantao Formation sandstone in this sag exhibits characteristics where the eastern part is superior to the western part,and the lower section of the Guantao For-mation is superior to the upper section.The water temperature of the sandstone geothermal wells in the Guantao Formation ranges from approximately 68 to 85℃.The water volume for a single well is between 106 and 155 m3/h,and the hydrochemical solution is primarily Cl-Na,with a salinity of around 10000 to 30000 mg/L.The Upper Quaternary and Minghuazhen Formation have a combined thickness of approximately 1200 m and serve as a good cap rock.The source of geothermal water is primarily replenished by atmospheric precipitation in the western and southwestern mountainous areas.This water then undergoes deep heat conduction and warming be-fore laterally replenishing the thermal reservoir.The geothermal resources of the thermal reservoir are approxi-mately 2245.41 × 108 GJ,with annual exploitable geothermal resources amounting to 5.61 × 108 GJ,which is equivalent to about 1.92 × 106 t of standard coal.The annual exploitation of geothermal resources can support a heating area of approximately 6770 × 104 m2,demonstrating substantial development potential.
geothermal systemgenetic modelresource evaluationsandstone geothermal reservoirGuantao FormationZhongmu Sag
万方数据
维普
